blip
A small, brief problem or change that does not last.
A blip is a small, temporary change or interruption that doesn't last long or mean much in the bigger picture. When your internet connection has a blip, it cuts out for just a second or two before working again. If your grades have been excellent all year and you get one bad test score, a teacher might call it just a blip, meaning it's a brief dip that doesn't change your overall pattern of success.
Today, we use the word blip for anything that's small and temporary: a blip in the power supply, a blip in sales numbers, or a blip in someone's concentration.
When something is just a blip, it means people usually don't worry too much about it. If a basketball team loses one game after winning ten straight, the coach might say, “That loss was just a blip,” to remind players not to panic. The phrase suggests that temporary setbacks happen, but they don't change the fundamental direction you're heading.